Yep, I do work with garnets - I'm trained as a gemologist, and am a member of the Soc. of Jewellery Historians, and the JPH (Jewellery, Plate and Horology) private club. I've the equipment to cut and polish stones, facetted and cabochons, as well as make jewellery. I also experiment with period cutting and polishing techniques. One of my present hobbies is enamelling based on the writings of theophilious. I'm tempted to make a replica of the Alfred Jewel, complete with the rock crystal top, although using silver, rather than gold, for budget reasons.

I've only made one replica with the thin slice method - mainly because of the time and costs involved. You need high carat gold (23ct or better) to make the cell walls with. Many original pieces actually were made of copper alloy and gilded for strength and cost reasons, but the cell inserts were still gold.

Mad Monk of Mitcham wrote:Agree that some is made from re-cycled pieces, especially the "Knot of Hercules". I'm not so sure about red glass - transparent red glass was made from colloidal gold, and is a reall bu**er to get right, it also has chemical issues. Opaque red/orange is easy and relatively common, but transparent reds are extremely rare, I've not heard of a confirmed one in fact.

Ahh, I was getting my gold and garnet bling mixed up. It's a couple of the 6th century Crimean pieces in the B-D collection that have faux garnetry made from glass. They feature transparent pale brown glass inlays with red ochre behind them and transparent red glass (apparently coloured with manganese) backed by tin foil.

Mad Monk of Mitcham wrote:Agree that some is made from re-cycled pieces, especially the "Knot of Hercules". I'm not so sure about red glass - transparent red glass was made from colloidal gold, and is a reall bu**er to get right, it also has chemical issues. Opaque red/orange is easy and relatively common, but transparent reds are extremely rare, I've not heard of a confirmed one in fact.

Ahh, I was getting my gold and garnet bling mixed up. It's a couple of the 6th century Crimean pieces in the B-D collection that have faux garnetry made from glass. They feature transparent pale brown glass inlays with red ochre behind them and transparent red glass (apparently coloured with manganese) backed by tin foil.

While glass is not my main interest, I am interested in faking stones. Early glass used manganese as a clarifying agent. Exposure to UV light will, in time, make it go lavender (see this article about its use in relatively modern pieces: http://www.patternglass.com/this_color_purple_99.htm)

The red colour was almost entirely due to ochre. Transparent Red stones were adifficult to fake with glass in pre-rennaisance times, so lots of interesting methods were used, mainly backings and occasionally trapping a layer of colour between two transparent stones, a technique known as soude stones, and are relatively common in medieval pieces.

Before anyone asks, I study fakes so that I can understand and recognise them. I will only sell synthetic / assembled / treated stones to people who know what they are buying. Stones have been faked for at least 9000 years, and there are some indications going back 35, 000 years. Pliny writing in the first century talks about fake garnets made with glass, probably of the soude type.

Is the gold matrix that holds the garnet in place soldered together with the garnet or soldered seperately then the garnet added later? Garnet can resist a lot of heat before it looks like it would do bad things and soldering the whole lot together looks a lot easier.

Hobbitstomper wrote:Mad Monk, I have a question about gold/garnet jewellery.

Is the gold matrix that holds the garnet in place soldered together with the garnet or soldered seperately then the garnet added later? Garnet can resist a lot of heat before it looks like it would do bad things and soldering the whole lot together looks a lot easier.

No soldering at all. The joining method used was diffusion bonding, where a copper plating is applied chemically, then the whole is heated to the eutectic temperature, so that the surface copper/gold alloy melts and bonds. Since the eutectic temperature is less than the melting temperature of gold, you do not end up with a puddle of gold.

Once you have the gold mesh, you fill the base of each cell with gunk, lay an embossed gold foil on it, trim the garnet to shape, shove in the garnet, and burnish it over.